JACK

From the ALSA wiki

Contents

What is JACK?

Jack is a low-latency audio server that can connect the input and
outputs of a number of audio applications. It is different from other
audio server efforts in that it has been designed from the ground up to
be suitable for low-latency professional audio work.

Jack and audio mixing

Since jack was designed for professionals and low latency, by default it
opens the first hardware device it find, usually "hw:0.0". Unlike most
applictions, it does not automatically route thru dmix. This means that
if you want to mix several audio streams in software for output, the
streams must talk to jackd. To force jackd to use dmix instead, allowing
other apps to function as normal (but adding latency to jack) it was
suggested the following command be used:

jackd -d alsa -P default :0

(This does not work on all systems)

How to use oss2jack and Skype

Salvatore Di Pietro \<salvuz_78 at virgilio dot it> explains: Well
,it's not that complicated... I went to